Does the smelly kiwi need deodorant to protect it from predators?

Does the natural mushroom-like smell of the kiwi bird help to make it a tempting target for the predators that are eating it out of existence? One scientist thinks so, and he is proposing a deodorant of some kind to protect the birds from extinction.

With all five kiwi species endangered, this is research that you shouldn't turn your nose up at. For the first several thousands of years of their existence, New Zealand kiwis (genus Apteryx) did not have to worry about what they smelled like—there were no mammals there to sniff them out, let alone eat them. That changed when humans came to the island, bringing stoats, rabbits, dogs, cats, pigs and a variety of other hungry critters.

Now Jim Briskie, an associate professor of behavioral ecology at the University of Canterbury in Christchurch, New Zealand, has an idea to help the kiwis: create a way to minimize the birds' aroma so they are less vulnerable to predators. He was recently awarded about $442,000 to research why the birds have not evolved to mask their odor, as have so many other species.

"Down the line if we do find some species are particularly smelly or vulnerable, perhaps I can design a deodorant for kiwis," Briskie told New Zealand's The Press. Just to be clear, he's not actually proposing the equivalent of an underarm stick for the birds—they don't have arms, after all—but perhaps something that would minimize the odor of their nests.

The kiwi's distinctive scent comes from the wax it secretes to preen its feathers. Briskie compared the substance with that produced by birds in Australia, which did evolve in an environment with natural predators, and found that the continental birds did not emit as strong a scent. He thinks that the presence of predators induced the Australian birds to mask their smells, perhaps through natural selection, an adaptation that birds in New Zealand never had a chance to acquire.

Briskie will now spend the next three years gather wax samples from several rare New Zealand bird species, including kiwis and the critically endangered kakapo parrot, which will be sent to a lab in Germany for testing. He hopes this will reveal which species' smells make them more vulnerable to predators.

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